August 26, 2013

Unearthed Ancient Roman Structure Predates Invention Of Mortar

Archaeologists digging at a long-buried city in Italy have unearthed a massive stone monument dating back at least 300 years before the Colosseum and 100 years before the invention of mortar. The new discovery indicates that the ancient Romans had developed architectural skills much earlier than previously believed.

The team of 60 researchers, including 35 undergraduates and 15 graduates, from the University of Michigan and Yale University were on hand this summer to work at the site. The excavation of the city is expected to continue through 2014, but with the new discovery under their belt, the archaeologists are hoping the $2 million U-M Museum of Archaeology-funded project will be extended.

The unearthed ancient structure was found at a site known as Gabii, which sits just east of Rome. The monument, a giant “Lego-like” stone block structure, is about half the size of a football field and dates back to between 350 and 250 BC. Nicola Terrenato, a U-M classics professor and lead scientist on the project, believes it could be the earliest public building ever discovered and said this is the largest American dig in Italy in the past half century.

He said the massive complex, which might also have been a private residence, “holds a stone retaining wall, geometrically patterned floors and two terraces connected by a grand staircase.”

This is unlike anything we thought the Romans were capable of building at the time, noted Terrenato, who added that it challenges an ancient stereotype that these people were a “modest and conservative people” at this period in history.

"There are a lot of constructive details that are beautiful to look at and they tell us more about how the Romans were building at that stage," Terrenato said. "This shows us they were beginning to experiment with modifying their natural environments—cutting back the natural slope and creating a retaining wall, for example— about a quarter of a millennium earlier than we thought."

While this site was built at least 300 years before the Colloseum, it does represent a critical step in the process that leads to later architecture, he said.

Perhaps of more interesting note is the fact that each of the massive stone blocks used to build the structure weighed thousands of pounds, something not considered a standard size used during this early period. But it makes sense because larger stones gave the structure more stability seeing mortar had not been invented yet.

"This is like Lego construction," Terrenato said. "They stacked them one on top of each other without any glue binding them together. This is the only technique they had access to and it must have been the desire for this kind of grand construction that drove them to the invention of mortar about 125 years later."

Many historians have labeled the Romans as a conservative people who only became lavish after soldiers returned from conquering Greece, bringing the extravagance of their culture home with them. But this new monument predates the extravagant lifestyle theory by a longshot.

"Rome conquered Greece in the 140s BCE. Roman historians said the soldiers came back and wanted Greek luxury, which is way of trying to shift blame," Terrenato said. "We now know that long before they conquered Greece, the Romans were already thinking big. This tears apart the view of Romans in this period as being very modest and inconspicuous."

The Gabii excavation site, which sits on a parcel of undeveloped land in modern-day Lazio, was once a major city that waned by the third century as the Roman Empire grew. The Gabii Project is meant to show what a city in this region looked like before the great Roman development period. Because the site itself sits outside Rome, the team is able to explore the site on a much deeper scale – something that would have not been possible within city limits due to centuries of continued building atop ancient sites.

The research team said about 60 percent of this massive building has been uncovered.

"Even though we could not observe the complex in its entire extent, we know we are dealing with a monument without parallels in the region, including Rome," said Marcello Mogetta, project managing director and a U-M doctoral student in classical art and archaeology. "My bet is that this will become a benchmark in future surveys of Roman architecture."

Andrew Johnson, an assistant professor of classics at Yale University, noted that this find has educational impacts.

"In the longer term, this is a discovery that we expect will radically change our understanding of Roman Republican history and archaeology," he said. "But more immediately, our students are returning from the field to the classrooms of their home institutions—Michigan, Yale and over a dozen others—with a new set of skills, methodologies, approaches and questions that we hope will enrich and inform their studies in various academic disciplines in manifold ways."

Terrenato and colleagues previously unearthed a 1,000-pound lead coffin at the Gabii site.